1. Field of Invention
This invention relates to the purpose of benzoxazine derivative, in particular to application of 2,3-dihydro-3-hydroxymethyl-6-amino-[1,4]-benzoxazine in preparation of drugs inducing embryonic stem cells to differentiate to vascular endothelial cells.
2. Description of Related Art
The structural formula of 2,3-dihydro-3-hydroxymethyl-6-amino-[1,4]-benzoxazine is as follows:

Molecular formula: C9H12N2O2 
Molecular weight: 180.2 Property: light yellow solid, melting point: 154-156° C. 2,3-dihydro-[1,4]-benzoxazine derivative belongs to a kind of very important structural units, and many natural products and synthetic drugs contain the structural unit.
The known 2,3-dihydro-2-substituted-[1,4]-benzoxazine derivatives have pharmacological activities of resisting bacteria, thrombus, bradycardia, central nervous system (CNS) disorders and the like, such as 2,3-dihydro-2-substituted-[1,4]-benzoxazine derivative structures involved in patents with the patent No. of U.S. Pat. No. 6,649,610, WO2005051934 and WO2005058847; 2,3-dihydro-2,3-substituted-[1,4]-benzoxazine derivatives are provided with pharmacological activities of analgesic, sedative, laxative and the like, such as 2,3-dihydro-2,3-substituted-[1,4]-benzoxazine derivative structures involved in patents with the patent numbers of GB1285711, GB1182770 and GB883324. In addition, 2,3-dihydro-[1,4]-benzoxazine compounds containing substituent on other locations (such as nitrogen and benzene ring) have the pharmacological effects of muscle relaxant, analgesic, anti-psychiatric disorders, anti-Parkinson, anti-inflammation, antipyretic, prevention of coronary heart disease and atherosclerosis, inhibition of phosphodiesterase and the like, such as 2,3-dihydro-[1,4]-benzoxazine derivative structures involved in patents with the patent numbers of U.S. Pat. No. 3,879,522, GB1173942, WO8907596, WO2004087694, WO0230914 and JP2000327663. However, people's research on structures, activity and synthesis of 2,3-dihydro-3-substituted-[1,4]-benzoxazine derivatives is rare, only including 2,3-dihydro-3-methyl-[1,4]-benzoxazine derivatives involved in patents with the patent numbers of U.S. Pat. No. 6,872,823 and US2006014946, and the compounds are mainly used as important intermediate for synthesizing quinolone antibacterial drugs and plant protection agents. The preparation methods include: 1) Three-step reaction preparation with 2,3,4-trifluoro-aniline and 2-hydroxy-propionate as raw materials, involved in U.S. Pat. No. 6,872,823; 2) Reduction preparation with 5% Pt/C by the aid of o-phenoxy acetone in isopropyl alcohol, involved in U.S. Patent US2006014946.
According to retrieval by the authority, the research on 2,3-dihydro-3-hydroxymethyl-6-amino-[1,4]-benzoxazine inducing embryonic stem cells to differentiate to vascular endothelial cells has not been reported at home and abroad currently.